Closing tool for outstanding sheet-metal seams



Sept. 15, 1959 c. F. ENGEL T 2,903,988

CLOSING TOOL FOR OUTSTANDING SHEET-METAL SEAMS Filed Feb. 25, 1957 FgR 39 TO POW SOURCE INVENTOR.

G e I 3 b CHARLES F. ENGEL. 8.

DAVID NORMAN DE WOSKIN ATTORNEY United States Patent CLOSING TOOL FOR OUTSTANDING SHEET-METAL SEAMS Charles F. Engel, Sparta, 111., and David Norman De Woskin, Clayton, M0., assignors to Engel Sheet Metal Equipment, Inc, St. Louis, Mo., a corporation of Missouri Application February 25, 1957, Serial No. 641,960

2 Claims. (Cl. 113-57) This invention relates to a new bending tool for closing outstanding sheet-metal flanges from 90 to 180 position, and in particular to a tool for closing so-called government lock type seams, by which adjacent sections of rectangular sheet-metal ducts are joined to each other.

The problems of closing this type of seam will be discussed hereinafter, in connection with a consideration of the accompanying drawings, in which:

Figure 1 is an exploded view showing the new tool in perspective, save for certain power and control elements therefor which are shown by symbols;

Figure 2 is a side View showing only the tool of Figure 1, assembled and in fully open position, the phantom lines showing its position in initial contact with a flange portion of a government lock seam. The duct sections and their flanges are shown schematically; and

Figure 3 is a side elevation corresponding to Figure 2 showing the tool in its fully closed position.

Government lock seams, such as shown in Figures 2 and 3, are widely prescribed in Federal specifications for the installation of ducts. Frequently it is necessary to install much of the duct work close to ceilings, beams, and other obstructions which limit the working space, particularly at the upper surface of the duct.

To close an outstanding sheet-metal flange from a 90 bend to a 180 bend has heretofore required preliminary hammering to reduce the angle to less than 90, and then either final hammering or clinching. None of these operations can readily be performed within limited space. Their expense has been high, and uniform closing around all four sides of the duct has been impossible. When exposed, the closed seams have been unsightly; when concealed, as on the upper side of ducts, they have seldom been fully closed.

Accordingly, the purposes of the present invention include providing a power'tool by which a strong, uniform, positive closing force may be readily exerted along such seams; one which is remotely controlled; which locks itself in position against the seam as it closes, then releases itself as it opens; provides the maximum of portability; and which utilizes a high mechanical advantage, despite limited space, by minimizing the overall height of the tool when in open position, so that the operator may insert his hand thereover for adjusting it in position along the seam. Additional purposes will be manifest from the following description.

Referring now to the drawings by the numbers of the detailed parts, the tool utilizes a preferably rectangular rugged steel frame generally designated 10, in which a rectangular back bar 11, a pair of side members 12, and

a front bar 13 are rigidly joined, as by welding. The

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size of a mans hand. Preferably the height of the back bar 11 and the side members 12 is equal and fairly shallow, say 1 /2 to 2.", in order to minimize the over-all working height.

The back bar 11 includes midway along its inner side a vertically cut notch 14, and a horizontally drilled aperture 15, which passes through the entire length of the back bar 11, across the notch 14, and defines a rear pivot axis z. Through the drilled aperture 15 is inserted a rear hinge pin 16, which extends preferably the entire length of the back bar 11 and serves within the notch as the rear pivot for a linear actuator hereinafter described.

The front bar 13 is also referred to hereinafter as the fixed bar. It is not rectangular in cross-section, although the greater part of its principal working surface, referred to hereinafter as the anvil face 17, is perpendicular to the under side of the front bar of the frame 10 as a whole, straight from end to end, and preferably planar; as the anvil face 17 serves as a Working surface against which the seam is formed. If for some purpose the seam ought to be formed at an angle apart from the perpendicular, the face 17 could be modified from the perpendicular. Similarly, certain departures from planarity, such as the presence of small grooves or some curvature, may not interfere with its functioning in the manner hereinafter described. The height of the anvil face 17 is greater than that of the outstanding sheetmetal flange hereinafter described.

As an aid to understanding the dimensional limitations of the tool, Figures 2 and 3 should be considered. Depicted in Figure 2 are adjacent duct section elements a, b, of rectangular duct sections to be joined together by a government lock seam. Each of the elements a, b and the successive duct elements joining therewith may have at its right end (as shown for the element a) a simple bent-up rectangular flange c, to serve as the male part of the lock to be closed. At its left end (as shown for the element b) the sheet-metal of each duct element is bent to form a female lock part, as follows: first, back against its outer surface, thence outward at for a distance greater than the height of the flange c, and then again forward at 90, providing in effect an integral bent U-channel designated d facing forward and lying outward of and adjacent the surface of the element b.

That portion of the integral channel d which is bent back against the duct outer surface is referred to hereinafter as the inner flange e; the portion adjacent it which extends outward perpendicularly to the surface of the element b, as the web 7, and the portion which projects forwardly therefrom toward the open end of the duct element b, as the outer flange g. These portions connect at bend radii, the radius juncture or portion between the inner flange e and the web 1 being of principal significance. The height of the web 1 is greater than that of the rectangularly outward flange c on the duct element a; and the outer flange g of the bent U-channel d is of lesser length than the web 7.

The anvil face 17 of the front bar 13 does not start at its under surface, but at a distance thereabove substantially equal to the bend radius portion between the inner flange e and the Web 1. Between the anvil face 17 and the under side of the tool, the front bar 13 has a concave radius portion 18 jutting forward from the plane of the anvil face 17, its curvature corresponding to the outer side of the U-channel radius portion, and extending to an edge juncture with the under side of the front bar 13, whereby to constitute a toe projection 19 for engaging beneath and against the outside of the channel bend, as shown.

Above the level of the anvil face 17 (and permissibly above the level of the side members 12 and the back bar 11), the fixed bar- 13 has a pair of fulcrum lugs 20,

3 proiecting above and forward beyond the anvil face, the lugs 20 being divided from each other, each located inwardly adjacent the outer margin defined by one of the. side members 12. Preferably the combined length ofthe fulcrum lugs 20 is somewhere near half the length of the fixed bar 13.

The lugs 20 are drilled longitudinally along a fulcrum axis 2: parallel to the rear pivot axisz, to provide aligned bores 21, the said axes being also parallel to the anvil face 17. The x axis is forward of the anvil face 17 a distance preferably equal to at least. three thicknes e O sheet-metal such as used inthe duct elements a, I1,

On a fulcrum pin 22 which extends through the bores 2 is mounted a wiper lever generally designated 23, by means of its fulcrum bore 24 drilled through its mid.- portion. Projecting forwardly from the fulcrum axis x when the lever 23 is in the substantially horizontal open position of Figure 2, is a wiper bar portion 25 of sub .stantially the same length as the anvil face 17 of the fixed bar 13, the bar portion 25 having a wiper face 26,011 that side which is presented downwardly when the wiper lever 23 is substantially horizontal, The wiper face 26 is rotatable downward and backward toward the anvil face 17 for closing as shown in Figure 3.

Extending aft when the wiper lever 23 is in open posi tion as shown in Figure 2, from the fulcrum axis x, the wiper lever 23 has a yoke-like lever arrn portion 27 including a vertical backward-facing notch 28. The yoke portions of the arm 27 are connected by a forward actuator pivot pin 29 secured on a horizontal forward pivot axis y parallel to the fulcrum axis x and rotatable thereabout as shown in Figures 2 and 3. When the tool is closed as shown in Figure 3, the extreme margin 30 of the wiper face 26 presses toward the anvil face somewhat above the level of the toe projection 19 Actuation of the wiper lever 23 is effected through an actuator rod fitting 31 pivotally mounted on the forward pivot pin 29 within the yoke of the lever arm portion 27, under force applied by the rod 32 of a hydraulic cylinder linear actuator 33. The rear end of the hydraulic cylinder 33 includes a backward-projecting support fin 34 horizontally drilled to provide a pivot bore 35 for mounting on the rear hinge pin 16.

Within the actuator 33 is a conventional hydraulic piston, not shown, moving positively with the flow of hydraulic fluid from a pump hereafter mentioned through flexible high-pressure hydraulic lines or tubes 36 which connect to each end of the actuator cylinder 33 and make a circuit with such pump. The unbroken lines of Figure 2 of the drawings show the position of the tool when the piston is substantially fully bottomed toward the back end of the actuator 33; the phantom lines of Figure 2. show its position with the actuator rod 32 partially extended; while Figure 3 shows the position with the actuator rod 32 fully extended.

The fluid which flows through the hydraulic lines 36 is moved positively in either direction by a hydraulic pump 37 powered by a reversible electric motor 38 under the control of a reversing switch 39 having three positions, forward, reverse, and 01f. Electrical power is supplied to the motor 38 subject to a series connection including a pressure switch 40 responsive to the hydraulic pressure within the pump 37, so that when pressure builds up to a pre-selected level the power to the motor 38 is cut off. Such pressure build-up occurs at both the extreme positions shown in Figures 2 and 3.

The tool so described is used in the following manner: It is placed in position against the outer surface of a duct section such as the section b, with its anvil face 17 abutting the outer side of the web 1 and the radius portion 18 in contact with the outer side of the bend radius between the inner flange e and the web f. The wiper lever 23 is in substantially horizontal open position as shown in Figure 2. The operator then operates the switch 39 for forward position, the motor 38 turning the pump 37 to force, the hydraulic fluid through the lines 36 in such direction as to extend the linear actuator rod 32. In extending, the forward end of the actuator 33 rises as the forward pivot pin 29 is elevated above the fulcrum pin 22, accompanying doWnWard-and-aft rotation of the Wiper bar portion 25. As the Wiper face 26 contacts the forwardprojecting edge of the outer flange g, it exerts a force thereon perpendicular to the then position of the wiper face 26, as shown by the small arr w in F gur 2... Such for e. is directed fir t Som what toward the toe projection 19 and then, as the Wiper face 26 gradually closes, progressively more horizontally, thus wiping the outer flange g downward and backward from the bend shown in Figure 2 to the closed bend shown in Figure 3. The forward spacing of the fulcrum axis x relative to the anvil face 17 (advantageously more than three metal thicknesses, so as to exert a tight closing force and accommodate some increase in metal thickness) results in the exertion of a force more backward than downward; the latter would tend to lift the tool upward. However, the toe projection 19, extending into the area between the duct surface b and the inner flange e, effectively locks the tool therein when the wiper bar portion 25 assumes the position shown in phantom lines in Figure 2. fionsequently, the tool is capable of exerting strong forces throughout the range of its closing movement without any tendency to dislodge itself from the seam. As the seam is fully closed with the outer flange g parallel to the web 1 and pressing the flange 0 between them, the pressure switch 40 tie-energizes the motor 38.

When the operator actuates the switch 39 to reverse position; the tool unlocks itself from the seam and the lever 23 returns to horizontal position, when the motor is again dewenergized. The tool may then be readily moved along the duct surface and regctuated as. many times as may be necessary to close the entire seam length.

In spaces immediately beneath ceilings, and otherwise where operating space is at a minimum, it is particularly convenient to have the wiper lever 23 horizontal when open and the actuator cylinder 33 thus lowered partly between the side members 12. Enough space is provided between the side members 12 around the cylinder 33 to permit the operator to grasp the cylinder, utilizing it as a handle for positi ning the tool when open. As it begins o lo e it locks itself in place; hence the operator may r m v hi hand before the tool reaches its maximum height shown in Figure 3.

Modifications of the specific embodiment shown and herein describ d will oc ur to hose familiar wi h the art- I-[ence this invention is not to be construed narrowly, but as fully coextensive with the claims. In them, the terms up and outward mean away from the duct surf f wa me n oward the seam and backward means away from it. Other terms of direction are .used in their obvious relations.

We claim:

1- For locking a he t-metal scam y b n ng back Par ll l to i we h o t r f ange of a ben U-channel whose inner flange lies adjacent a surface and whose web extends substantially perpendicular ,to such surface, a tool comprising a fixed oar having a straight portion positionable against the outer side of such web, a wiper lever having a rum a d being m un ed thereby to t e fixed bar forwa of i s sa d st a h po on and above the l l f su h h n l ou dance t e w p l ver i ng a Wiper bar se l n th co c no ds subs an tially with that of the fixed bar, the wiper lever having an arm xt ding b y nd the ful um ppo te aid wiper t er mpr s n a rame in n s de m mbers ext n ing backwa d rom th fixed ba pac d f om each oth a s u ing a ea actua or suppor betwe n them and r mote f om t fixed bar. n a tua n me s. sup: ed b we n sa d spa d. sid member by a d rear support and said lever arm, whereby to raise somewhat upward when the wiper bar is closed downward.

2. A tool as defined in claim 1, the portion of said fixed bar so positionable against said web having at its lower edge a projection extending forwardly thereof for engaging the outside of the 'bend joining such channel web and its inner flange, the wiper bar having a wiper surface closable downward and backward toward the straight portion of the fixed bar at a level above said projection.

References Cited in the file of this patent UNITED STATES PATENTS Wagner June 16, 1885 Delaney June 30, 1891 Flagge July 21, 1914 Beatty Oct. 10, 1939 Hunt Mar. 2, 1948 

